This invention relates to elastomeric grade crossing panels, and in particular to the interconnection of several such panels to form integral grade crossing units.
Elastomeric grade crossing panels have come into wide use because they provide a smoother more durable crossing than other types of material. Panels of this general type are described in Trickel et al., U.S. Pat. No. 4,365,743. The panels typically are rubber and are cast in an enclosed mold. The panels normally are narrower than a roadway and thus several panels must be placed end-to-end to form the crossing. These individual panels are not heavy enough to prevent them from being lifted, and thus displaced, when vehicular traffic passes over them, so they must be attached to the ties that support them. Attaching the crossing panels to the ties not only is labor intensive, and thus increases the cost of the crossing, but it makes it difficult to remove the crossing to retamp the ballast that supports the ties. In addition, while the panels can be attached to wood ties with fasteners, attaching them to concrete ties creates more of a problem.
The subject invention overcomes the difficulties associated with attaching elastomeric grade crossing panels to ties by interconnecting the panels to one another to create integrated crossing units which are sufficiently heavy that they do not have to be attached to the ties.
When elastomeric grade crossing panels are formed it is desirable to place cylindrical metal rods in the mold in order to speed curling. Thus, cylindrical passageways are formed in the finished panels. These rods are tapered in order to facilitate their removal from the panels, which causes the passageways to be tapered also. The subject invention utilizes these passageways to interconnect the panels by providing pins which extend into the passageways of adjacent panels. The pins are divided into a larger end, which fits into the larger end of the tapered passageway located at one end of the panel, and a smaller end, which fits into the smaller end of the tapered passageway located at the other end of the panel. The pins preferably are made from an elastomeric material in order to grip the panels. If the pins are elastomeric they preferably have a metal core to increase their rigidity.
In one embodiment of the invention, the pins are attached to the panels with an adhesive. In addition, the abutting edges of the panels are adhered to one another with an adhesive. This permits the panels to be interconnected in advance and transported and installed as an integral unit. In this embodiment the panels have attachment devices installed in them for lifting the combined crossing units with a crane or back hoe. The attachment devices are movable between retracted positions where they are stored in the panels and extended positions where they project from the panels.
In a second embodiment of the invention, the panels are interconnected as they are installed and an adhesive is not used. In either case each integrated crossing unit is sufficiently heavy that it will not lift when driven on. Thus, the panels do not have to be attached to the ties. However, with time the crossing units will move along the tracks and eventually become displaced from the roadway. To prevent this from occurring, end restraints are placed at each end of the crossing. The end restraints are attached to the ties using conventional attachment techniques.
Accordingly, it is a principal object of the subject invention to interconnect adjacent elastomeric grade crossing panels to one another to create integral crossing units.
It is a further object of the subject invention to provide such crossing units which can be transported and installed as a single unit.
It is a still further object of the subject invention to provide such crossing units having integral attachment devices to facilitate lifting the crossing unit with a crane or back hoe.
The foregoing and other objectives, features and advantages of the present invention will be more readily understood upon consideration of the following detailed description of the invention taken in conjunction with the accompanying drawings.